In order to gain access for repair and maintenance it is necessary to provide removable panels in the form of fairings or closures about engine structures or airframes. Accordingly, these panels must be easily removable, but also must be securely located whereby the panel will not become detached in use causing damage to associated engine parts or airframes, both of the aircraft upon which the panel is secure as well as other aircraft in the vicinity.
Previously, it has been known to provide hinged panels which extend from a hinge edge of an opening or gap. Thus, the panel can pivot about that hinge edge until securely located normally by an opposed latching edge of the opening or gap. Normally, the closure panel is secured about a pin with a hook like clasp or a number of such hooks extending over the pin to allow pivot thereabout. In such circumstances it is possible to remove the panel completely rather than requiring the closure panel to be propped for access.
Unfortunately, such detachment of the closure panel from the hinge edge requires upon reassembly accurate association between that hinge edge and a pivot edge of the closure panel in order to create the necessary pivot association between the pin and hook-like clasps. Sometimes this pivot association may not be appropriately formed by failure to ensure engagement between the hook-like clasps and the pin, but with limited vibration and load, the panel will remain in place. Nevertheless, when vibration and other loads are then placed upon the closure panel it may become detached with detrimental consequences.
FIGS. A and B in the attached drawings illustrate respectively an exploded representation of a typical aircraft engine propulsion system and a cowling edge seal. Referring to FIG. A, it can be seen that the engine propulsion system comprises a number of cowling panels and elements and in particular, a nose cowl 100 with side cowls 101, 102 and further cowls 103 associated with the core engine components 104. These cowls 100 to 103 cool and protect the engine core 104. The present invention is directed to cowl panels 101, 102, 103 and other cowl or fairing panels which are secured through hinge elements 105 located in a hinge support structure 106 about the core 104 or similar. Thus, as indicated above it is difficult to locate hinge elements such as elements 105 in the hinge support structure 106 which is generally located within a pylon nose cover 107. In such circumstances, an appropriate robust hinge may not be fully formed such that the panels 101, 102 may become detached in operation. This problem is further exacerbated by the use of a “V” groove circumferential seal 110 between the panels 101, 102 and reciprocal parts of the nearest cowl 100 or core 104. This “V” groove association in both the leading and trailing edges of the panels 101, 102 provides significant friction association which may retain the panel in position when not under load even when a proper hinge has not been formed between the elements 105 and support structure 106.
FIG. B provides a cross-sectional detail of such a “V” groove seal arrangement 110. Thus, a fixed rigid structure on the engine core 104 or casing 100 provides a “V” groove 111 within which an edge 112 of a panel 113 is located to form a seal. There is a friction engagement between the edge 112 and the “V” groove 111 which provides a seal but also helps grip the panel 113 in order that it is retained about the core 104 despite the lack of good association between the hinge elements 105 and the support 106.
It will be appreciated that as indicated above there are a number of fairings and cowlings within an engine system and the above description with regard to side cowls 101, 102 is merely by way of example. Thus, there will be similar problems with regard to an engine core cowl 103 in its association with a hoop plate 107.